HALIFAX — As the federal Liberals start their search for the big ideas that will fuel their reelection campaign next year, their policy convention in Halifax this weekend has made at least one thing clear: pharmacare is front of mind.

Even before delegates voted the creation of a national pharmacare program as their top priority, it was clearly the policy that generated the most excitement on the convention floor.

The Liberals know they face a challenge in the 2019 election. Burdened...